It is one of the longest-running mysteries in the NFL: How is Marvin Lewis still coach of the Bengals?

It says plenty about both the sorry history and the fascinatingly low expectations of the Cincinnati franchise since founder Paul Brown’s death 22 years ago that Lewis is both the longest-tenured and winningest sideline boss in team history.

What makes Lewis such a mystifying anomaly in today’s win-or-else NFL is his laughable playoff record. He never has won a postseason game in 11 seasons with the Bengals, going 0-3 in that span and missing out entirely seven of those years.

Though Supreme Court justices might seem to have less job security than Lewis does with owner Mike Brown, Sunday afternoon’s intriguing home matchup with Aaron Rodgers and the Packers is a great chance to help Lewis build some national credibility.

The table does appear set in 2013 for the Bengals to finally make a breakthrough into the league’s upper echelon under Lewis and — dare we say it — even win a playoff game or two in a very weak AFC.

Not only has Cincinnati assembled the deepest and most talented roster in its division, but the AFC North as it’s currently constructed certainly looks like it offers the Bengals a clear path to the postseason.

The Ravens might be the reigning Super Bowl champions, but they were decimated by the salary cap in the offseason and are in rebuilding mode, along with the similarly cap-depleted Steelers.

And the North’s other team, the perennially sad-sack Browns, appeared to raise the white flag on their season this week with the shocking Trent Richardson trade.

Lewis’ Bengals are indeed the class of their division, and they need to start acting like it. Cincinnati certainly didn’t in Week 1, blowing a double-digit lead in the second half in a loss to the Bears, but rebounded earlier this week to strangle the Steelers.

Now the Bengals get Rodgers and the red-hot Packers offense, which obliterated the Redskins last week in a 38-20 game that wasn’t even that close.

Green Bay became the first team in NFL history to have a 450-yard passer (Rodgers), and a 125-yard rusher (James Starks) in the same game, and the Packers go into Cincinnati with an offense ranked No. 1 in the league in yards and No. 2 in scoring.

With a porous defense that’s conversely ranked third from the bottom in yards allowed, Green Bay looks like it offers the Bengals their best chance since “Hard Knocks” this summer to make the rest of the league sit up and take notice.

The Packers give up points and yards in bunches, which means Cincinnati’s Andy Dalton can show he is more than just the pedestrian quarterback he was much of last year and in the first two games this season.

Dalton certainly has been surrounded with weapons. Speedy rookie scatback Gio Bernard has been a revelation, and the Bengals already boasted one of the league’s most explosive receivers in A.J. Green.

Now is the time for Lewis to start turning all his team’s potential into results — and victories that count. It’s probably not going to happen Sunday, but it’s a long season and the Bengals appear to be built for the long haul.